نشریه تحقیقات منابع طبیعی تجدید شونده
سال هفتم شماره 3 (پیاپی 25، پاییز 1395)

Today, one of the most important challenges facing human societies is global warming and reduces biodiversity. For the present study, Elevation profile Veisar forests west of Mazandaran were selected. To calculate the biomass of tree and vegetation diversity in the forest, in a profile height (700 to 1,500 meters above sea level) was 9 floors and on each floor of 8 plots with the exception of 1500 meters above sea level with 5 floors and a total of 69 plots of 400 square meters plots (20 × 20 m) were taken All the trees in each plot, diameter at breast height of 7/5 cm of coverage and type of species identified and measured. The measurement data herbaceous plant cover, a micro-plot of 100 square meters (10 × 10 m) in the center of the plot on foot and herbal species of plant cover percentage were measured according to Braun-Blanquet method. The value of carbon sequestration by combining the relationship between size, density dry and carbon coefficient was calculated. After determining the levels defined by common measurements to determine the relationship between indicators of biological diversity (richness, evenness, diversity) and Carbon Analysis of variance was used. The findings showed that between the amounts of biomass amount of carbon stored in trees with no significant relationship between diversity indices in elevation. These results suggest that proper management of forest biomass for appropriate monitoring research in the area of biodiversity indices cannot be used as a means.

The purpose of this study is to evaluate the physical and mechanical properties of papers made of tree branches as a cellulose source. The branches of the tree Platanus orientalis plain region of Astara and the Kraft pulping process used. For the process of chemical baking soda in varying levels 10, 14, 16, 18 and 20 percent based on the dry weight of plantain wood chips were used. Also the cooking time considered in three levels of 60, 80 and 100 minutes. Cooking temperature and the cooking sulfidity in all cases remained at a constant level of 165 degrees Celsius and 25 percent, respectively and Liquor ratio plantain chips are based on standard laboratory Digester 8 to 1. Also to make handmade paper, pulp freeness were refined to reach about 25 ± 350 ml. 60 grams handmade paper were prepared of refined pulps and it’s Resistance and mechanical properties were measured. Statistical analysis of features of handmade paper based on completely randomized design factorial test, and strength features of handmade paper of the ANOVA and Duncan's test was used to compare the average. Strength properties of the produced kraft pulp by the bursting index, tensile index, folding index, rupture index and brightness, were 55/5(Kpa cm2/g), 10082(Nm/g), 55(n), 53/6(mNm2/g) and 32/53(percent), respectively.

The aim of this research was study about of natural durability of Wood Plastic Composites with modified wood flour. Chemical modification of wood flour in 4 levels without treatment, Mercerization, Benzylation and Acetylation as variables of this research were considered. Process of material mixing performed by extruder machine and the test samples with way of injection molding were made. The test samples at periods of 8, 12 and 16 week in the vicinity of Trametes Versicolor with a temperature of 25 ° C and 75% relative humidity according to the BS 838: 1961 standard respectively. Mass reduction of composite and wood flour as well as the reduction of test criteria was measured. In order to ensure the chemical modification of wood flour and to know the amount of wood flour by chemical reaction respectively of tests of infrared spectroscopy (FTIR) and Weight Percent Change (WPG) were used. Thermal properties of Wood Plastic Composites at different levels of decay analysis (TGA) were performed. To study the morphology of composites made from Scanning Electron Microscope (SEM) was used. The results showed that the effect of chemical modification of wood flour, mass reduction of Wood Plastic Composites and mass reduction of wood flour decreased. So that the best mechanism of chemical modification in controlling decays, was Acetylation treatment. The most percentage of weight changes was related to Benzylation treatment. The results of the thermal properties of Wood Plastic Composites showed that with the increasing decay was a sharp drop in thermal properties. The results of infrared spectroscopy perform chemical modification of wood flour confirmed. Microscopic images showed that with increasing time of decay, was added to the cracks and gaps in the composites but in effect of chemical modification, especially in the treatment of Acetylation and Benzylation the cracks are significantly reduced.

Knowledge of the recent changes as an essential component of global environmental changes and sustainable part of the study emerged. The destruction of landscape, vegetation and land use changes and land cover change are those who constantly exert pressure on the country's environment. Land use change is a complex process and dynamic that natural and human systems linked together and make a direct impact on soil, water and atmosphere. The aim of this study was to investigate the possibility of using indicators of ecological landscape in the separation of land and plant communities in the study area is in the North East Semnan. To this end, there is need to the morphology of the land and vegetation maps. In this study, six metrics at class level and one metric at landscape-level for the study area were measured. These metrics using Patch analyst extension in ArcGIS was calculated. Then, using PCA important measures for separation plant communities were determined. Principal component analysis to determine the most important metrics in the resolution of the morphology map of land classes showed edge density, number of patches and mean patch size are the most important metrics, and in separate classes plant communities of this area the class area proportion, number of patches and mean patch fractal dimension are the most important metrics

In this study, chemical compounds in the extractives of three rice cultivars (Hashemi, Amrollahi, and Neda) in Mazandaran province were analyzed using gas chromatography-mass spectrometry (GC/MS). The milled rice stems were prepared and extracted based on TAPPI standard. The results showed that 8 chemical compounds were identified for Amrollahi and Hashemi cultivars and 4 chemical compounds for Neda cultivar. The most abundant chemical compounds measured in extractives of Amrollahi, Hashemi, and Neda cultivars were N-butyl-formamide, 4-hydroxy-4-methyl-2-pantanone and 2-pantanone, respectively. Three compounds of Benzene, Tetradecane and 1-2-Benzendicarboxylic acid were common compounds in the rice cultivars studied. The amount of the 3 recent compounds in Hashemi were higher than other cultivars. In addition to three mentioned compounds, the combination of 4-hydroxy-4-methyl-2-pentanone was common in Amrullahi and Hashemi cultivars, so that the percentage of this compound in Hashemi cultivar was more than Amrollahi cultivar. Acetic acid and N-Hexadecanoic acid are also common in Hashemi and Neda cultivars. There was no common composition in extractives of rice stems with Amrollahi and Neda cultivars.

The aim of this study is to define some growth performances and survival rate of European whitefish larvae when they were fed with three different feeding regimes until fingerlings stage. One hundred and fifty newly hatched white fish fry (40.01 mm initial total length) randomly stocked into nine rearing net cages in a natural pond of Khojir research center, and nourished for 90 days with three kinds of food including rotifer (Brachionus plicatilis), rainbow trout commercial diet and a compound of rainbow trout commercial diet with live feed in a mixture of 50% of each. First month of rearing revealed that different feeding regimes cause significant differences between all groups (p<0.05). The highest body gain (48.000.231 %), length gain (23.650.116 mm), specific growth rate (5.360.002%) and feed efficiency (63.480.539%) was obtain in the fish fed with live food in the first month of trial (p<0.05). Also the same trend was observed in the second month of growing. However, in the third month of growing all growth indices except survival rate are improved in commercial diet in comparison to other groups (p<0.05). According to results, whitefish larvae fed with rotifers as a live feed is recommended up to two months of rearing